Wipe-on phosphating composition



United States Patent 3,346,426 WIPE-0N PHOSPHATING COMPOSITION Louis Schlossberg, Oak Park, Mich., assignor to Detrex Chemical Industries, Inc., Detroit, Mich., a corporation of Michigan No Drawing. Filed Apr. 22, 1964, Ser. No. 361,882 4 Claims. (C1. 1486.17)

This invention relates to an improved phosphate coating composition for ferrous and galvanized surfaces. More particularly this invention relates to such a composition which is adapted to be utilized as a wipe-on treatment.

It is known to treat ferrous and galvanized surfaces with phosphatizing composition for the purpose of increasing the paint ibonding performance of the treated surface. Among other developments directed to such phosphatizing treatments, may be cited US. Patents Nos. 2,121,574; 2,293,716; 2,351,605; 2,375,468; 2,657,156; 2,743,204; and 2,877,148. Some of these require particular equipment, such as for example multistage treating processes including cleaning, rinsing, phosphatizing, and subsequent chromate treatment, such stages being operated with or without the addition of heat. This results in an expensive phosphatizing treatment, and is not readily adaptable for use in such locations as job shops, auto maintenance and repair centers, and other small establishments where it may be desirable to apply a phosphatizing composition to ferrous or galvanized surfaces. Other developments utilize dangerous acid treatments such as treatments involving the use of nitric and sulfuric acids.

It is an object of this invention to provide a phosphating composition which may readily be used to provide a paint bonding phosphate coat on steel and galvanized surfaces by merely wiping on such composition.

It is another object of this invention to provide such a phosphating composition which does not require heat in the wipe-on application.

3,346,426 Patented Oct. 10, 1967 Percent by weight Ingredient: of solution Zinc 0.128- 3.84 Phosphoric acid (100%) 0.400l2.00 Glycolic acid 0.070- 2.10 2,4-dinitrobenzenesodiumsulfonate 0.039- 1.17

The foregoing solution may include additionally a nonionic surfactant for simultaneous cleaning, such as, for example, a polyoxyethylene compound. Such a surfactant may effectively be used at a concentration of from about 0.01 percent to about 0.6 percent by Weight of the aqueous solution,

In the examples shown in Table 1, aqueous solutions were prepared containing varying concentrations of ingredients, as shown. Standard 4 in. by 12 in. mild steel panels were then treated with the solution of each example at room temperature by roll coating for two minutes each using a short nap roller coater. Each panel was then rinsed in tap water for one half minute and dried. The dried panels were each coated without priming with 1 /2 mils of an acrylic paint which was baked at 300 F. for 30 minutes. Following baking and cooling to room temperature, the painted panels were scribed and exposed in an ASTM B117-61 salt spray cabinet. After 65 hours of such exposure, the panels were removed and examined for evidence of paint creep from the scribe.

TABLE I [Ingredients expressed as percent by weight of aqueous solution] 2,4-dinitro- Polyoxy- Ex. Zn (Cale. H3PO4 Glyeolie benzeneethylene Max. Creep Rating from ZnO) Acid sodium Surfactant at Scribe sulfonate 0. 064 0. 20 0. 035 0. 0195 0.005 Very poor. 0. 128 0. 40 0. 07 0. 039 0. 01 Excellent. 0.32 1. 00 0. 175 0. 0975 0. 05 D0.

1. 92 6. 00 1.05 0. 341 0.30 D0. 1.92 6.00 1.05 0.39 0.30 Do. 1. 92 6. 00 1.05 0.535 0.30 Do. 1.92 6.00 1.05 1.17 0.30 Do. 2.55 8.00 1. 0.78 0.40 D0. 3. 20 10.00 1. 75 0.975 0.50 D0.

3. 84 12. 0O 2. 10 1. 17 0.60 Nil Do.

4. 48 14.00 2. 1. 36 0.70 19 mm Very poor.

4 v Percent by weight Ingredient: of solution Zinc (calc. from ZnO) 0.128- 3.84 Phosphoric acid (100%) 0400-1200 2,4-dinitrobenzenesodiumsulfonate 0.039- 1.17

2. The composition of claim 1 wherein said solution contains additionally a polyoxyethylene surfactant in an amount of from about 0.01 percent to about 0.6 percent by Weight of the aqueous solution.

3. An aqueous phosphate coating composition containing in solution a composition consisting esentially of:

TABLE 11 [Ingredients expressed as percent by weight of aqueous solution] 2,4-dinitro- Polyoxy- Ex. Zn (Cale. HQPO; Glycolic benzeneethylene Max. Creep Rating from ZnO) Acid sodium Surfactant at Scribe sulfonate 21 1.92 6.0 0 0.585 0.3 3mm Good. 2: 1. 92 6.00 0. 535 0 0.3 9mm Poor. 23 1.92 6 0 0.293 0. 293 0.3 Nil Excellent.

It is obvious from the above description and the ex- Percent by Weight amples that the wipe-on phosphating composition of this lflgfedlenti of solution invention is particularly advantageous in the provision of 1 L Is q Z110) 0128- superior paint bonding performance with the accompanyhfzg g g g (100%) ----'--I- mg easy apphcatlon of a wlpe on process Many Small 2,4-dinitrobenzenesodiumsulfonate 0.039- 1.17

metal coating operations not previously adaptable to phosphate coating treatments, may now readily utilize such treatment to commercial advantage.

While in accordance with the provisions of the statutes, I have illustrated and described the best form of embodiment of my invention now known to me, it will be apparent to those skilled in the art that changes may be made in the formulation of the composition described herein without departing from the spirit and scope of the invention as set forth in the appended claims.

Having thus described my invention, I claim:

1. An aqueous phosphate coating composition containing in solution a composition consisting esentially of:

4. The composition of claim 3 wherein said solution contains additionally a polyoxyethylene surfactant in an amount of from about 0.01 percent to about 0.6 percent by weight of the aqueous solution.

References Cited ALFRED L. LEAVITT, Primary Examiner.

R. S. KENDALL, Assistant Examiner. 

1. AN AQUEOUS PHOSPHATE COATING COMPOSITION CONTAINING A SOLUTION A COMPOSITION CONSISTING ESENTIALLY OF: 